Trifluoroacetic acid → HCID 22710169, compound

Participants

Reaction Steps

In tetrahydrofuran (10 ml) was dissolved 1-tert-butoxycarbonyl-2-carboxymethyl-4-[(5-chloroindol-2-yl)sulfonyl]piperazine (1.00 g), followed by the addition of carbonyldiimidazole (1.06 g). The resulting mixture was heated overnight under reflux. After cooling to room temperature, the reaction mixture was added with benzenesulfonamide (685 mg), 1,8-diazabicyclo[5.4.0]-7-undecene (0.64 ml) and carbonyldiimidazole (353 mg). The resulting mixture was heated under reflux for 1 hour. The reaction mixture was then concentrated under reduced pressure. Dichloromethane was added to the residue and the solid thus precipitated was filtered off. The filtrate was washed successively with 1N hydrochloric acid and saturated aqueous NaCl solution. The organic layer was dried over anhydrous sodium sulfate and distilled under reduced pressure to remove the solvent. The residue was purified by chromatography on a silica gel column (Φ3.0×10.0 cm, dichloromethane:methanol=100:1), whereby pale brown foam was obtained. The resulting foam was dissolved in dichloromethane (10 ml), followed by the addition of trifluoroacetic acid (10 ml). After stirring at room temperature for 1 minute, the reaction mixture was concentrated under reduced pressure. Diethyl ether was added to the residue and the resulting precipitate was collected by filtration, whereby the title compound (496 mg, 31%) was obtained as colorless foam.

Provenance & Evidence